1. Field of the Invention
The present invention relates to a circuit component built-in module that contains an active component such as a semiconductor and a passive component such as a capacitor and a method for manufacturing the circuit component built-in module.
2. Description of the Related Art
With recent advances in small high-performance electronic equipment, there has been a growing demand for a semiconductor having high density and high performance. This also requires a circuit board that can achieve a smaller size and a higher density. Accordingly, a circuit component built-in module has been proposed that includes active and/or passive components and vias for electrically connecting those components and wiring patterns. Moreover, when circuit components are contained in a substrate, it is necessary to improve the heat dissipation or to adjust the thermal expansion coefficients of the substrate and the circuit components. For this purpose, a circuit component built-in module that uses a substrate material including an inorganic filler and a thermosetting resin also has been proposed (see, e.g., JP 11(1993)-220262 A and JP 2001-244638 A).
FIG. 38 is a cross-sectional view showing the configuration of a conventional circuit component built-in module (JP 2001-244638 A). In FIG. 38, reference numeral 701 is an electrical insulating substrate made of a composite material that includes an inorganic filler and a thermosetting resin, 702 is wiring patterns, 703 is a circuit component such as a semiconductor, 704 is vias for electrically connecting the wiring patterns, and 705 is a sealant for sealing a connecting portion between the circuit component and the electrical insulating substrate.
The conventional circuit component built-in module is suitable for flip-chip mounting in which the circuit component (e.g., a semiconductor) is connected with its terminals facing the wiring pattern, but not for wire bonding. For the flip-chip mounting, the circuit component and the wiring pattern are bonded generally via a metal projection of about 20 μm to 100 μm. Therefore, the gap between them is small, i.e., about 20 μm to 150 μm. In some cases an anisotropic conductive film or paste is often used, and in other cases the gap is sealed while the circuit component and the wiring pattern are bonded together. For the wire bonding, aluminum or gold wires are used to make connection. The wires generally have a diameter of 20 μm to 40 μm and a length of 0.5 mm to 3 mm. Compared with the flip-chip mounting, the wire bonding is likely to undergo a shape change such as deformation or deflection due to the above features of the wires. Thus, when the conventional circuit component built-in module is produced without using a sealant that protects the connecting portion and the wires in a process of embedding the circuit component, the resin can flow and exert a force on the wires as the circuit component is embedded in the resin. Consequently, the wires are separated and moved, resulting in a short circuit between the wires. As described above, the conventional circuit component built-in module cannot employ a low cost mounting technique such as wire bonding, which has been used widely as a general method for mounting a semiconductor of a circuit component built-in module.